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.\"     @(#)colcrt.1	8.1 (Berkeley) 6/30/93
.\"
.TH COLCRT "1" "September 2011" "util-linux" "User Commands"
.SH NAME
colcrt \- filter nroff output for CRT previewing
.SH SYNOPSIS
.B colcrt
[options]
.RI [ file ...]
.SH DESCRIPTION
.B colcrt
provides virtual half-line and reverse line feed sequences for terminals
without such capability, and on which overstriking is destructive.
Half-line characters and underlining (changed to dashing `\-') are placed on
new lines in between the normal output lines.
.SH OPTIONS
.TP
\fB\-\fR, \fB\-\-no\-underlining\fR
Suppress all underlining.  This option is especially useful for previewing
.I allboxed
tables from
.BR tbl (1).
.TP
\fB\-2\fR, \fB\-\-half\-lines\fR
Causes all half-lines to be printed, effectively double spacing the output.
Normally, a minimal space output format is used which will suppress empty
lines.  The program never suppresses two consecutive empty lines, however.
The
.B \-2
option is useful for sending output to the line printer when the output
contains superscripts and subscripts which would otherwise be invisible.
.TP
\fB\-V\fR, \fB\-\-version\fR
Display version information and exit.
.TP
\fB\-h\fR, \fB\-\-help\fR
Display help text and exit.
.SH HISTORY
The
.B colcrt
command appeared in 3.0BSD.
.SH BUGS
Should fold underlines onto blanks even with the
.B '\-'
option so that a true underline character would show.
.PP
Can't back up more than 102 lines.
.PP
General overstriking is lost; as a special case '|' overstruck with '\-' or
underline becomes '+'.
.PP
Lines are trimmed to 132 characters.
.PP
Some provision should be made for processing superscripts and subscripts in
documents which are already double-spaced.
.SH EXAMPLES
A typical use of
.B colcrt
would be:
.PP
.RS
.B tbl exum2.n \&| nroff \-ms \&| colcrt \- \&| more
.RE
.SH SEE ALSO
.BR col (1),
.BR more (1),
.BR nroff (1),
.BR troff (1),
.BR ul (1)
.SH AVAILABILITY
The colcrt command is part of the util-linux package and is available from
.UR https://\:www.kernel.org\:/pub\:/linux\:/utils\:/util-linux/
Linux Kernel Archive
.UE .
